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Defense Support Program Satellites

Mission

Air Force Space Command-operated Defense Support Program (DSP) satellites are a key part of North America's early warning systems. In their 22,300-mile, geosynchronous orbits, DSP satellites help protect the United States and its allies by detecting missile launches, space launches and nuclear detonations.

Features

DSP satellites use an infrared sensor to detect heat from missile and booster plumes against the Earth's background.  In 1995, technological advancements were made to ground processing systems, enhancing detection capability of smaller missiles to provide improved warning of attack by short-range missiles against U.S. and allied forces overseas.

Numerous improvement projects have enabled DSP to provide accurate, reliable data in the face of evolving missile threats.  On-station sensor reliability has provided uninterrupted service well past their design lifetime.  Technological improvements in sensor design include above-the-horizon capability for full hemispheric coverage and improved resolution.  Increased on-board signal-processing capability improves clutter rejection.  Enhanced reliability and survivability improvements were also incorporated.  Legacy DSP satellites are now controlled by the Space Based Infrared System (SBIRS) ground station.  To learn more about SBIRS, please reference the SBIRS Fact Sheet.

Background

The program came to life with the first launch of a DSP satellite in the early 1970s.  Since that time, DSP satellites have provided an uninterrupted space-based early warning capability.  The original DSP satellite weighed 2,000 pounds and had 400 watts of power, 2,000 detectors, and a design life of 1.25 years.  Throughout the life of the program, the satellite has undergone numerous improvements to enhance reliability and capability.  The weight grew to 5,250 pounds, power to 1,516 watts, number of detectors increased to 6,000, and the design life has increased to a goal of five years.

The 460th Space Wing, with headquarters at Buckley Air Force Base, Colorado, has operates DSP satellites and report warning information, via communications links, to the North American Aerospace Defense Command/U.S. Northern Command and U.S. Strategic Command early warning centers within Cheyenne Mountain Air Force Station, located near Colorado Springs, Colorado.  These centers immediately forward data to various agencies and areas of operations around the world.

Typically, DSP satellites were launched into geosynchronous orbit on a Titan IV booster and inertial upper stage combination.  However, one DSP satellite was launched using the space shuttle on mission STS-44 (Nov. 24, 1991).  The final DSP satellite was launched on the new Evolved Expendable Launch Vehicle (EELV) Delta-4, Heavy, in November 2007.

DSP's effectiveness was proven during Operation Desert Storm, when DSP detected the launch of Iraqi Scud missiles and provided warning to civilian populations and coalition forces in Israel and Saudi Arabia.  Legacy DSP satellites continue to contribute to detecting missile and space launches under SBIRS.

General Characteristics

Primary mission:
strategic and theater missile launch detection
Contractor: Northrop-Grumman
Weight: 5,250 pounds (2,386 kilograms)
Orbit altitude: approximately 22,300 miles (35,970 kilometers)
Power plant: solar arrays generate 1,516 watts
Height: 32.8 feet (10 meters) on orbit; 28 feet (8.5 meters) at launch
Diameter: 22 feet (6.7 meters) on orbit; 13.7 feet (4.2 meters) at launch
Date deployed: 1970
Latest satellite block: sats 18-23
Unit cost: $400 million
Operational inventory: classified

Point of Contact: Air Force Space Command, Public Affairs Office; 150 Vandenberg St., Suite 1105; Peterson AFB, Colo., 80914-4500; 692-3731 or (719) 554-3731. 

(Current as of November 2016)